The present invention relates to an electrochromic display cell and, more particularly, to a novel construction of an electrochromic display cell which ensures a high legibility.
The electrochromic display cell generally comprises transparent electrodes, electrochromic layers formed on the transparent electrodes, and a porous ceramic plate for providing a white background. A typical construction of the electrochromic display cell is disclosed in U.S. Pat. No. 3,944,333 entitled "ELECTROCHROMIC DISPLAY WITH POROUS SEPARATOR" issued on Mar. 16, 1976.
When the electrochromic layer is placed in the coloration condition, the operator recognizes the colored segment. When the electrochromic layer is placed in the bleached condition, the operator observes the porous ceramic plate through the transparent electrode. Since the transparent electrode, in the conventional cell, is formed to accommodate the segment configuration and its lead electrode configuration, there is a color tone difference between the background which is observed through the transparent electrode and the background which is not covered by the transparent electrode. This color tone difference deteriorates the display quality.
Accordingly, an object of the present invention is to provide an electrochromic display cell for ensuring a clean display.
Another object of the present invention is to provide an electrochromic display cell which ensures a uniform background.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, transparent electrodes are formed on a front glass substrate to substantially cover the entire display surface of the electrochromic display cell. Each of the transparent electrodes are separated from each other by a thin gap. Accordingly, the operator observes the porous ceramic plate through the transparent electrode on the substantially entire display surface, whereby a uniform background is observed.